[gnome-software] Avoid redownloading the same screenshots for different images

[Joaquim Manuel Pereira Rocha <jrocha src gnome org>]

commit 196d48a6866ad915f8ecb59703256b60c7a611da
Author: Joaquim Rocha <jrocha endlessm com>
Date:   Wed Nov 9 22:07:00 2016 +0100

    Avoid redownloading the same screenshots for different images
    
    When screenshots only have one image assigned to them, then this
    image will be used for the thumbnail and normal sizes. These
    changes prevent repeating a download of the same file by saving
    screenshots under those conditions already in the thumbnail and
    normal sizes.

 src/gs-screenshot-image.c |   96 ++++++++++++++++++++++++++++++++++++++------
 1 files changed, 83 insertions(+), 13 deletions(-)
---
diff --git a/src/gs-screenshot-image.c b/src/gs-screenshot-image.c
index 23b7b2d..219e881 100644
--- a/src/gs-screenshot-image.c
+++ b/src/gs-screenshot-image.c
@@ -199,6 +199,85 @@ gs_screenshot_image_show_blurred (GsScreenshotImage *ssimg,
        }
 }
 
+static gboolean
+gs_screenshot_image_save_downloaded_img (GsScreenshotImage *ssimg,
+                                        GdkPixbuf *pixbuf,
+                                        GError **error)
+{
+       g_autoptr(AsImage) im = NULL;
+       gboolean ret;
+       const GPtrArray *images;
+       g_autoptr(GError) local_error = NULL;
+       g_autofree char *filename = NULL;
+       g_autofree char *size_dir = NULL;
+       g_autofree char *cache_kind = NULL;
+       g_autofree char *basename = NULL;
+       guint width = ssimg->width;
+       guint height = ssimg->height;
+
+       /* save to file, using the same code as the AppStream builder
+        * so the preview looks the same */
+       im = as_image_new ();
+       as_image_set_pixbuf (im, pixbuf);
+       ret = as_image_save_filename (im, ssimg->filename,
+                                     ssimg->width * ssimg->scale,
+                                     ssimg->height * ssimg->scale,
+                                     AS_IMAGE_SAVE_FLAG_PAD_16_9,
+                                     error);
+
+       if (!ret)
+               return FALSE;
+
+       if (ssimg->screenshot == NULL)
+               return TRUE;
+
+       images = as_screenshot_get_images (ssimg->screenshot);
+       if (images->len > 1)
+               return TRUE;
+
+       if (width == AS_IMAGE_THUMBNAIL_WIDTH &&
+           height == AS_IMAGE_THUMBNAIL_HEIGHT) {
+               width = AS_IMAGE_NORMAL_WIDTH;
+               height = AS_IMAGE_NORMAL_HEIGHT;
+       } else {
+               width = AS_IMAGE_THUMBNAIL_WIDTH;
+               height = AS_IMAGE_THUMBNAIL_HEIGHT;
+       }
+
+       width *= ssimg->scale;
+       height *= ssimg->scale;
+       basename = g_path_get_basename (ssimg->filename);
+       size_dir = g_strdup_printf ("%ux%u", width, height);
+       cache_kind = g_build_filename ("screenshots", size_dir, NULL);
+       filename = gs_utils_get_cache_filename (cache_kind, basename,
+                                               GS_UTILS_CACHE_FLAG_WRITEABLE,
+                                               &local_error);
+
+        if (filename == NULL) {
+               /* if we cannot get a cache filename, warn about that but do not
+                * set a user's visible error because this is a complementary
+                * operation */
+                g_warning ("Failed to get cache filename for counterpart "
+                           "screenshot '%s' in folder '%s': %s", basename,
+                           cache_kind, local_error->message);
+                return TRUE;
+        }
+
+       ret = as_image_save_filename (im, filename, width, height,
+                                     AS_IMAGE_SAVE_FLAG_PAD_16_9,
+                                     &local_error);
+
+       if (!ret) {
+               /* if we cannot save this screenshot, warn about that but do not
+                * set a user's visible error because this is a complementary
+                * operation */
+                g_warning ("Failed to save screenshot '%s': %s", filename,
+                           local_error->message);
+        }
+
+       return TRUE;
+}
+
 static void
 gs_screenshot_image_complete_cb (SoupSession *session,
                                 SoupMessage *msg,
@@ -255,19 +334,10 @@ gs_screenshot_image_complete_cb (SoupSession *session,
                        gs_screenshot_image_set_error (ssimg, error->message);
                        return;
                }
-       } else {
-               /* save to file, using the same code as the AppStream builder
-                * so the preview looks the same */
-               im = as_image_new ();
-               as_image_set_pixbuf (im, pixbuf);
-               ret = as_image_save_filename (im, ssimg->filename,
-                                             ssimg->width * ssimg->scale,
-                                             ssimg->height * ssimg->scale,
-                                             AS_IMAGE_SAVE_FLAG_PAD_16_9, &error);
-               if (!ret) {
-                       gs_screenshot_image_set_error (ssimg, error->message);
-                       return;
-               }
+       } else if (!gs_screenshot_image_save_downloaded_img (ssimg, pixbuf,
+                                                            &error)) {
+               gs_screenshot_image_set_error (ssimg, error->message);
+               return;
        }
 
        /* got image, so show */